{
  "button":[
      <volist name="list" id="vo" key="k">
      {          
          <empty name="vo.child">
          "name":"<{$vo.name}>",          
          "type":"<{$vo.type}>",
          <eq name="vo.type" value="click">"key":"<{$vo.keyword}>"<else/>"url":"<{$vo.url}>"</eq>
          <else/>
          "name":"<{$vo.name}>",
          "sub_button":[
            <volist name="vo.child" id="r">
            {  
               "type":"<{$r.type}>",
               "name":"<{$r.name}>",
               <eq name="r.type" value="click">
               "key":"<{$r.keyword}>"
               <else/>
               "url":"<{$r.url}>"
               </eq>
            }<?php if($i<count($vo['child'])){echo ',';}?>
            </volist>
            ]
          </empty>          
      }<?php
      if ($k<count($list)) {
        echo ',';
      }
      ?>
      </volist>
  ]
}